Impact of Mid-and Upper-Level Dry Air on Tropical Cyclone Genesis and Intensification:A Modeling Study of Durian(2001)

The impact of mid-and upper-level dry air,represented by low relative humidity(RH)values,on the genesis of tropical cyclone(TC)Durian(2001)in the South China Sea was investigated by a series of numerical experiments using the Weather Research and Forecasting model.The mid-level RH was lowered in different regions relative to TC Durian(2001)’s genesis location.Results suggest that the location of dry air was important to Durian(2001)’s genesis and intensification.The rapid development of the TC was accompanied by sustained near-saturated mid-and upper-level air,whereas low humidity decelerated its development.Water vapor budget analysis showed that moisture at mid and upper levels was mainly supplied by the vertical convergence of moisture flux and the divergence terms,and consumed by the condensation process.The horizontal convergence of moisture flux term supplied moisture in the air moistening process but consumed moisture in the air drying process.With a dryer mid-and upper-level environment,convective and stratiform precipitation were both inhibited.The upward mass fluxes and the diabatic heating rates associated with these two precipitation types were also suppressed.Generally,convection played the dominant role,since the impact of the stratiform process on vertical mass transportation and diabatic heating was much weaker.The vorticity budget showed that the negative vorticity convergence term,which was closely related to the inhibited convection,caused the vorticity to decrease above the lower troposphere in a dryer environment.The negative vorticity tendency is suggested to slow down the vertical coherence and the development rate of TCs.

Liquid penetration of freeze-drying and air-drying wood of plantation Chinese fir

A comparative study was conducted on liquid penetration of the freeze-drying and air-drying sapwood and heartwood lumber of plantation Chinese fir （Cunninghamia lanceolata）. The maximum amount of dyeing solution uptake by the capillary rise method was used to evaluate the liquid penetration properties of the treated wood. The pit aspiration ratio was determined by semithin section method. Changes in wood microstructure were investigated using scanning electron microscopy. The results showed that compared with air drying, the freeze drying had a significant effect on liquid penetration of sapwood and heartwood of Chinese fir. The liquid penetration of sapwood is significantly higher than that of the heartwood for both drying treatments. Low pit aspiration ratio and cracks of pits membrane of some bordered pits are the main reasons for increasing liquid penetration after freeze drying treatment.

Mathematical Modeling and Effect of Various Hot-Air Drying on Mushroom(Lentinus edodes)

An experimental study was performed to determine the characteristics and drying process of mushroom （Lentinus edodes） by 6 different hot-air drying methods namely isothermal drying, uniform raise drying, non-uniform raise drying, uniform intermittent drying, non-uniform intermittent drying and combined drying. The chemical composition （dry matter, ash, crude protein, crude fat, total sugars, dietary fiber, and energy）, color parameters （L, a＊, b＊, c＊, and h~） and rehydration capacities were determined. Among all the experiments, non-uniform intermittent drying reached a better comprehensive results due to the higher chemical composition, better color quality associated with high bright （26.381＋5.842）, high color tone （73.670＋2.975）, low chroma （13.349a：3.456） as well as the highest rehydration （453.76% weigh of dried body）. Nine kinds of classical mathematical model were used to obtained moisture data and the Midili-kucuk model can be described by the drying process with the coefficient （R2 ranged from 0.99790 to 0.99967）, chi-square （X2 ranged from 0.00003 to 0.00019） and root mean square error （RMSE ranged from 0.000486 to 0.0012367）.

Effects of Chemical Osmotic Pretreatment on Drying Characteristics and Quality of Blueberry under Hot Air Drying

In order to study the effects of chemical osmotic pretreatment on the characteristics and quality of blueberry under hot air drying,fresh blueberries were pretreated with 2.5 g/100 mL K2CO3+0.6 g/100 mL olive oil,and 5.0 g/100 mL K2CO3+0.6 g/100 mL olive oil at(45±0.5)℃,respectively.The changes of water content,rehydration,hardness,microstructure,color difference,active ingredient anthocyanin,total phenol and DPPH radical scavenging capacity of dried blueberries in different treatment groups under hot air drying were compared and analyzed.The results showed that the dehydration rates of blueberries vary greatly according to the type of pretreatments when the samples were dried to the same water content with hot air.Specifically,the dehydration rate of dried blueberries pretreated by 5.0%K2CO3 solution was the highest,followed by 2.5%K2CO3 osmotic pretreatment and lastly the control group;the corresponding dehydration time was 10,14 and 20h,respectively.The physical qualities of dried blueberries,involving the browning degree,color difference,rehydration and microstructure,were significantly different between the chemical osmotic pretreatment group and the control group(P<0.05).The chemical osmotic pretreatment of K2CO3 solution increased the dehydration rate of the samples,shortened the drying time and maintained the quality of blueberries dried with hot air.There was no significant difference between the physical quality of dried blueberries pretreated by 2.5%and 5.0%K2CO3 solution(P>0.05),whereas there was significant difference in drying time and nutrient quality which is characterized by total phenols,anthocyanins,DPPH radical scavenging rate,soluble total sugar(P<0.05).Conclusion:5.0%K2CO3 osmotic pretreatment combining with hot air drying can improve the dehydration rate,shorten the drying time and maintain the physical and nutritional quality.

Artificial neural network techniques to predict the moisture ratio content during hot air drying and vacuum drying of Radix isatidis extract

Background:To predict the moisture ratio of Radix isatidis extract during drying.Methods:Artificial neural networks were designed using the MATLAB neural network toolbox to produce a moisture ratio prediction model of Radix isatidis extract during hot air drying and vacuum drying,where regression values and mean squared error were used as evaluation indexes to optimize the number of hidden layer nodes and determine the topological structure of artificial neural networks model.In addition,the drying curves for the different drying parameters were analyzed.Results:The optimal topological structure of the moisture ratio prediction model for hot air drying and vacuum drying of Radix isatidis extract were“4-9-1”and“5-9-1”respectively,and the regression values between the predicted value and the experimental value is close to 1.This indicates that it has a high prediction accuracy.The moisture ratio gradually decreases with an increase in the drying time,reducing the loading,initial moisture content,increasing the temperature,and pressure can shorten the drying time and improve the drying efficiency.Conclusion:Artificial neural networks technology has the advantages of rapid and accurate prediction,and can provide a theoretical basis and technical support for online prediction during the drying process of the extract.

Analysis and Modeling of Wangqing Oil Shale Drying Characteristics in a Novel Fluidized Bed Dryer with Asynchronous Rotating Air Distributor

In order to replace the conventional distributor, a novel asynchronous rotating air distributor, which can optimize the drying ability of fluidized bed and strengthen the drying performance of oil shale particles, is creatively designed in this study. The rotating speed of the asynchronous rotating air distributor with an embedded center disk and an encircling disk is regulated to achieve the different air supply conditions. The impacts of different drying conditions on the drying characteristic of Wangqing oil shale particles are studied with the help of electronic scales. The dynamics of experimental data is analyzed with 9 common drying models. The results indicate that the particles distribution in fluidized bed can be improved and the drying time can be reduced by decreasing the rotating speed of the embedded center disk and increasing the rotating speed of the encircling disk. The drying process of oil shale particles involves a rising drying rate period, a constant drying rate period and a falling drying rate period. Regulating the air distributor rotating speed reasonably will accelerate the shift of particles from the rising drying rate period to the falling drying rate period directly. The two-term model fits properly the oil shale particles drying simulation among 9 drying models at different air supply conditions. Yet the air absorbed in the particles' pores is diffused along with the moisture evaporation, and a small amount of moisture remains on the wall of fluidized bed in each experiment, thus, the values of drying simulation are less than the experimental values.

MECHANISM AND APPLICATION OF COAL DRY BENEFICIATION WITH AIR-DENSE MEDIUM FLUIDIZED BED

The mechanism of beneficiation with air dense fluidized bed has been theoretically studied in the paper. Focusing attention on the misplacing resources in separation process, the misplacing effects are divided into two parts called respectively as misplacing effect of viscosity and misplacing effect of motion. The proposed separation theory can reasonably explain the results of separation in different fluidization states. Experimental results in pilot and commercial plants showed that the air dense medium fluidized bed is a high efficiency dry cleaning technique. The dynamic stability of fluidized bed density is directly affected by the variation of fine coal content in fluidized bed and can be controlled in expected range through measurement of fluidized bed density and adjusting of split flow rate. With air dense medium fluidized bed, various coals of size 50—6 mm can be efficiently beneficiated. The separation density can be adjusted between 1.2—2.2 g/cm 3, and the probable error E p value is about 0.06.

EFFECT OF DRY COLD AIR ACTIVITY ON THE OFFSHORE RAPID INTENSIFICATION OF SUPER TYPHOON SAOMAI(2006): A NUMERICAL SIMULATION RESEARCH

Employing the mesoscale WRF(Weather Research and Forecast) model, Super Typhoon Saomai(2006) is simulated. The variation of track and intensity and its offshore rapid intensification process are well demonstrated by the model, and the temperature and humidity patterns associated with the dry cold air activity and their impact on and mechanism of the offshore rapid intensification of Saomai are mainly studied in this paper. The results indicate that high-resolution water vapor imagery can visually reveal the development, evolution, interaction as well as the mutual complementation of the dry cold air activity accompanied with the development of Saomai. The offshore rapid intensification phenomenon of Saomai is closely related to the dry cold air which originates from the upper- and mid-troposphere. Besides, the dry cold air from the upper troposphere is stronger than that from the mid-troposphere.Saomai intensifies as the dry cold air from the northwest moves toward its circulation but weakens when the dry cold air from the southwest is drawn into the storm. Dry cold airflows and their cold advection effect caused by the downward motion across the isentropic surface are favorable to the development of Saomai. The dry cold air always moves along an isentropic surface from the upper troposphere to the mid-troposphere around the typhoon circulation and contributes to Saomai's abrupt intensity change.

Effects of Air-Drying on the Inorganic Phosphorus Forms in Soils

After 90 days cultivation of five different plants (rye grass, lupin, buckwheat, rape and amaranth) in three soils (Yellowbrown soil, Paddy soil and Red soil), fresh soil samples were collected and inorganic phosphorus (Pi) fractions weremeasured before and after air-drying. The results clearly indicated that the total Pi and their composition differed significantlyamong soil types. The air-drying process increased the total Pi in yellow brown soil and in paddy soil, while decreased thatin red soil. The total Pi could vary to 70% of that before air-drying. The Pi forms in different soils changed to differentextent after air-drying. As to yellow brown soil, Al-P decreased, while O-P and Ca-P increased; as to paddy soil, Al-P andCa-P increased, while Fe-P and O-P remained; as to red soil, Al-P and Fe-P increased, Ca-P remained and O-P reducedobviously. Growth of different plants in soils had effects on Pi forms during the process of air-drying. Therefore, forchemical study of soil phosphorus, application of fresh soil samples can provide more reliable results.

Characteristics of Dry Cold Air Intrusion in a Typical Strong Storm

Taking a typical strong storm in Guizhou on April 5, 2017 for example, the diagnosis analysis used the water vapor cloud and the initial field of EC thin grid, including physical quantity, surface and upper air meteorological observation, as well as radar observation data. For the environment parameter analysis, small CAPE value tended to underestimate storm intensity on potential forecast stage, strong vertical wind shear revealed the strong dry cold air was the important intensity factors of the storm. The water vapor cloud map can be used to monitor the most important features, the dry zone, the wet zone and the boundary between them. When dry intrusion is found, it can be used as one of the bases for the development of heavy rain. Dry cold air intrusion on high-level was traced by water vapor images. And in this process, the analyses revealed the role of dry cold air’s influence on intensity of the storm.

Calculation and Design of Dry-type Air-core Reactor

Based on the method of compound and additional conditions under the conditions of the equal temperature rise and the equal potential drop (P.D.) of resistance, the application of design software of dry-type air-core reactor is introduced in this thesis. The analytical methods of the inductance are also given. This approach is proved entirely feasible in theory through the simplification with Bartky transformation, and is able to quickly and accurately calculate reactor inductance. This paper presents the analytical methods of the loss of dry-type air-core reactor as well.

Surface Roughness Evaluation in Dry-Cutting of Magnesium Alloy by Air Pressure Coolant

In this paper, a studying of surface roughness in dry milling with air pressure coolant of wrought magnesium alloy AZ31B will be carried out. The effects of air flow, feed-rate per tooth, cutting velocity and number of inserts in a cutting tool on surface roughness have been examined. Surface roughness increases with increasing feed-rate per tooth and increasing number of inserts in the cutting tool. However, it is nearly unchanged under a specific range of cutting velocity in the experiment and improved by the flow of air cooling.

Hot Air Drying and Quality of Red and White Varieties of Onion (Allium cepa)

This study was undertaken to investigate the drying characteristics of red and white varieties of onion (Allium cepa) in a convective dryer. The drying characteristics of onion slices were examined at air temperatures of 50℃, 60℃ and 70℃ and sample thicknesses of 2 mm. During the drying experiments, air velocity was held stable at 0.9 m/s. The effects of air temperature on the drying characteristics and quality parameters such as vitamins C and D, macro minerals (Mg, Na, P, Ca and K), non-enzymatic browning and thiolsulphinate of the dried onion slices were determined. For each of the plots of the drying curves from the mechanical drying tests, there was an absence of or just a very brief appearance of a constant rate period because onions are hygroscopic and hygroscopic foods tending to quickly enter the falling rate period;drying time decreased considerably with increased temperature. The time required to reduce the moisture content to any given value was dependent on the drying conditions, being the longest at an air temperature of 50℃, 0.9 m/s and the shortest at an air temperature of 70℃ and air velocity of 0.9 m/s. The loss of vitamin C, which is a thermo-sensitive compound, was the least at an air temperature of 50℃.

Dry Intrusion Analysis of A Heavy Rainstorm in Southern Shaanxi

[Objective] One regional rainstorm weather in the south area of Shaanxi was expounded.[Method] By employing the NCEP/NCAR 1°×1°reanalysis data,routine observation and automatic precipitation station data,the large scale circulation background field of regional precipitation in the south area of Shaanxi province from July 16-18 in 2010 was expounded.By dint of physical quantity such as the meridional wind,relative humidity and false relative temperature,the characteristics of dry intrusion and its role in rainstorm were expounded.[Result] The mild and high latitude at 500 hPa was stable.The continental high pressure and subtropical high pressure were stable.The 700 and 850 hPa shear lines or low vortexes were the main influence system that resulted into large scale of rainstorm in south Shaanxi.The landing typhoon had distinct influences on the importance of storm.The influence of typhoon and subtropical high was mutual.It not only formed and strengthened the torrent in the low air,also transmitted water vapor and energy incessantly to the south area of Shaanxi,playing an important role in augment of rainstorm.There were two distinct dry intrusions in the rainstorm process,showing a dense dry layer in the high layer of convective layer.The existence of dry layer was conductive to the accumulation of convective unstable energy in the low layer.The release of convective unstable energy could transmit warm and wet airstream in the low level to the higher level,being conductive to the occurrence of precipitation.The analysis of θse in the warp direction vertical profile suggested that there was frontal zone in this rainstorm process and the dry air activity in this rainstorm process was very strong.[Conclusion] The study provided theoretical reference to the forecast in future.

Indoor Environmental Quality of Air Conditioned Residential Buildings in Extreme Dry Desert Climate

In this study, the indoor environmental quality (IEQ) in air conditioned residential buildings in a dry desert climate is examined from the perspective of occupants via two aspects: thermal comfort and indoor air quality. The study presents statistical data about the domestic-occupant thermal comfort sensations together with data describing the indoor air quality in Kuwaiti residential buildings. With respect to the latter, the overall IEQ acceptance using two measurements namely: physical measurements and subjective information collected via questionnaires, was used to evaluate 111 occupants living in twenty five air-conditioned residential buildings in the state of Kuwait. The operative temperature based on Actual Mean Vote (AMV) and Predicted Mean Vote (PMV) was identified using linear regression analysis of responses on the ASHRAE seven-point thermal sensation scale and was found to be 25.2°C and 23.3°C, respectively, in the summer season. Indoor air quality (IAQ) with respect to carbon dioxide concentration level was compared with the acceptable limits of international standards, i.e. ASHRAE Standard 62.1 [1]. The proposed overall IEQ acceptance findings in residential buildings show CO2 concentration level between 909 and 1250 ppm. However, this may be considered a higher level of CO2 concentration, which may require increasing ventilation rate through window operation or mechanical ventilation.

Effects of Different Drying Processes on the Effective Components of Stichopus japonicus Viscera

Drying is a basic link in seafood processing, and the effects of forced air drying and vacuum drying on the effective components of Stichopus japonicus viscera were compared with the moisture, total saponin and polysaccharide contents as the detection indexes. The contents of effective components obtained using forced air drying were slightly lower than those obtained using vacuum drying, but the forced air drying method used short drying time and low economic energy consumption. Excellent drying effects and low cost of forced air drying made it can be adapted to the requirements of large-scale production applications.

Genetic Control of Air-Dried Wood Density, Mechanical Properties and Its Implication for Veneer Timber Breeding of New Triploid Clones in Populus tomentosa Carr

The wood samples of 9 triploid clones of Populus tomentosa Carr. taken from a 9 year old clonal test site were analyzed in order to investigate the genetic variation of wood properties, including air dried wood density and some mechanical properties. The results showed that significant or extremely significant difference in air dried wood density and the mechanical properties existed among the clones, this means these wood properties were under moderate or strong genetic controls and could be improved by genetic manipulations. The radial and vertical variation patterns of air dried wood density were also studied and the results were found to coordinate with other previous research results. The vertical variation patterns of most mechanical properties within the individual tree also conformed to the general wood theories except the modulus of elasticity and cross section hardness. Among the mechanical properties, modulus of elasticity (MOE) and tangent section hardness were under strong genetic control, with the clonal repeatabilities being 0 90 and 0 80, respectively. However, the clonal repeatabilities of other mechanical properties under study were a little lower than above two indexes. Genetic correlation analysis indicated that super clonal selection and breeding for veneer timber could be realized through indirect selection of wood density and form indexes.

Influence of Different Drying Temperatures on Quality of Balsam Pear Slices

[Objective] The aim was to investigate the effects of different drying temperatures on the physiochemical properties and antioxidant activity of balsam pear slices. [Method] Balsam pear slices were dried at different hot air temperatures, 40, 50, 60, 70 and 80 ℃. [Result] The polyphenols content was highest （2.83 mg/g） in the balsam pear slices dried at 50 ℃, and the flavonoids content was highest （2.584 mg/g） in those dried at 60 ℃. Different drying temperatures had a great impact on the antioxidant capacity of polyphenols in balsam pear. The balsam pear slices dried at 50 ℃ showed the strongest capacity for scavenging DPPH free radicals with IC50 of 0.015 mg/ml, and those dried at 80 ℃ showed the strongest capacity for removing ABTS free radicals with IC50 of 0.0689 mg/ml. [Conclusion] The hot air temperature of 50 ℃ had the least impact on the quality of balsam pear slices.

水稻秸秆营养穴盘热风辅助微波干燥工艺参数优化

为研究水稻秸秆营养穴盘在不同条件下的热风辅助微波干燥最佳工艺,以水稻秸秆营养穴盘的干燥速率和干燥后的形变量为指标,利用响应面研究微波功率、加热温度和热风速度对水稻秸秆营养穴盘热风辅助微波干燥工艺的影响,建立二次多项式的回归模型,并进行干燥工艺优化。结果表明:回归模型拟合性较高,可以较好地描述水稻秸秆营养穴盘的干燥过程;水稻秸秆营养穴盘热风辅助微波干燥的最佳工艺参数,即微波功率为1600 W、加热温度为60℃、热风速度为15 m/s时,干燥速率最快为4.015%/min,形变量最小为1.522 cm。研究结果可为促进水稻秸秆营养穴盘推广与应用提供重要的理论支撑及技术支持。

Experiment research on grain drying process in the heat pump assisted fluidized beds

A heat pump assisted fluidized bed grain drying experimental system wasdeveloped. Based on this system, a serial of experiments was performed under four kinds of air cycleconditions. According to the experimental analysis, an appropriate drying medium-air cycle for theheat pump assisted fluidized bed drying equipment was decided, which is different from the commonlyused heat pump assisted drying system. The experimental results concerning the drying operationperformance of the new system show that the averaged coefficient of performance (COP) can reach morethan 2.5. The economical evaluation was performed and the power consumption for removing a kilogramwater from grains was about 0.485 kW-h/kg (H_2O), which shows its reasonable commercial efficiencyand great application potentiality in future market.